The invention relates to a photographic modified retrofocus-type wide-angle lens.
U.S. Pat. No. 5,909,319 A has disclosed a lens in which the overall length does not change over the whole focusing path. As seen from the object side, the lens has, in the light direction, a first lens unit group with overall positive refractive power which contains a negative lens unit. The second and third lens unit groups, as seen in the light direction, each consist of a cemented element with negative refractive power and the fourth lens unit group has positive refractive power. The lens elements two and three are displaceably mounted for focusing purposes.
DE 33 45 987 A1 has disclosed a telephoto lens, in which the front lens unit group has positive refractive power, the intermediate lens unit group has negative refractive power and a rear lens unit group has positive refractive power. The intermediate lens unit group is subdivided into two subgroups, wherein the lens is focused by moving the two subgroups toward the image side while modifying the distance between the subgroups.